Snagging a High Fly Ball
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The outfield is big, but the mitt and the fly balls are small, so NASA is counting on quantity and a little luck to snare one or two. Web viewers at home will get a chance to see the more impressive fireballs, glowing as if they were hot line-drives.
The Perseids Live! balloon flight to about 33.5 km (110,000 ft) altitude will be NASA/Marshall's third mission to capture materials of cosmic origin before they are incinerated by entry into Earth's atmosphere or contact with the ground if they survive entry.
NASA/Marshall's first two flights were in November 1998 during the Leonids meteor shower and April 1999 during a meteor minimum to provide a proper comparison. On Perseids Live!, NASA/Marshall will continue experimenting with several types of capture media to see how they fare at high altitude, and with new equipment for tracking and imagery.
December 3: Mars Polar Lander nears touchdown
December 2: What next, Leonids?
November 30: Polar Lander Mission Overview
November 30: Learning how to make a clean sweep in space
GPS - the Global Positioning System - uses timing signals from satellites in high Earth orbit to calculate the receiver's position. The 12-channel system should measure the Perseids Live! balloon's horizontal location to within 100 meters (328 feet) and its altitude to within 152 meters (500 ft).
"That's within the size of a football field," Myszka said. "That's fairly good accuracy."
The payload will also include a new charge-coupled device (CCD) camera, an electronic retina similar in some basic respects to the Wide Field Camera aboard the Hubble Space Telescope.
The camera is more sensitive to light than the camera carried on the two previous missions, and has about double the resolution. Web viewers should have a better view of background stars and bolides - meteors' fiery trails - than on the two earlier missions.
The radio downlink, power supply, and other equipment are taken from the earlier missions. The transmitter also will be the same and will broadcast on channel 58 for cable-ready TV using an external antenna. This will be a line-of-sight signal that can only be received in the Southeast.
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The area-time product - 480 square centimeters for 2 hours - is comparable to that of a 1965 sounding rocket flight [a brief exposure with a larger sample area] which failed to return any detectable Leonid meteoroids.
Myszka said that the balloon package probably will not travel as far as the two previous balloons did.
"It will probably return to Earth closer to us," he said, "because the winds aloft have shifted as compared to the November 1998 and April 1999 launches." He anticipates landing will occur within 50 km (about 30 mi) of Redstone Arsenal where NASA/Marshall is located.Web Links
NASA/Ames Leonids MAC Workshop - April 12 - 15, 1999
Leonids' Particle Analyses from Stratospheric Balloon Collection on Xerogel Surfaces - conference abstract
Leonids Live! -site of the live webcast of the 1998 Leonids
Leonid Sample Return Update -- Apr. 1, 1999. Scientists will describe initial results from a program to catch meteoroids in flight at the NASA/Ames Leonids Workshop April 12-15, 1999.
The Ghost of Fireballs Past -- Dec. 22, 1998. RADAR echoes from Leonid and Geminid meteors.
Bunches & Bunches of Geminids -- Dec. 15, 1998. The Geminids continued to intensify in 1998
The 1998 Leonids: A bust or a blast? -- Nov. 27, 1998. New images of Leonid fireballs and their smokey remnants.
Leonids Sample Return payload recovered! -- Nov. 23, 1998. Scientists are scanning the "comet catcher" for signs of Leonid meteoroids.
Early birds catch the Leonids -- Nov. 19, 1998. The peak of the Leonid meteor shower happened more than 14 hours earlier than experts had predicted.
A high-altitude look at the Leonids -- Nov. 18, 1998. NASA science balloon catches video of 8 fireballs.
The Leonid Sample Return Mission -- Nov. 16, 1998. NASA scientists hope to capture a Leonid meteoroid and return it to Earth.
Great Expectations: the 1998 Leonid meteor shower -- Nov. 10, 1998. The basics of what the Leonids are and what might happen on November 17.
|For more information, please contact:
Dr. John M. Horack , Director of Science Communications
|Author: Dave Dooling
Curator: Bryan Walls
NASA Official: M. Frank Rose